Greetings from Lankayan Island: Dendritic Jawfish

Hello everyone,

Since I am going to be in Lankayan Island the whole year, I thaught it would be nice to report on some of the interesting species & news here in Lankayan. Lankayan is one of the islands within the Sugud Islands Marine Conservation Area (SIMCA).

On my first week here, I was brought to see Lankayan's famous jawfish. It was my first experience seeing this Dendritic jawfish. It was big and it has eggs in its mouth. It was a very interesting fish to observe and I immedietly look for more information on the fish.

Cheers,
-Salha-

Jawfish from the Family Opistognathidae (opisto means ‘behind’ and gnath means ‘mouth’ in Latin), are classified within Order Perciformes, Suborder Percoidei.

The Dendritic Jawfish is a large jawfish species and can grow up to approximately 25cm in length. It can be identified by its yellow brown body with dark spots and blotches. The species is solitary and usually can be found burrowing in sands and rubble bottom reef in depths ranging from 2m – 40m. In Langkayan Island, this jawfish is very famous. In fact one of the dive site here is named after them, Jawfish Lair.

Jawfish typically reside in burrows that they construct in sandy substrate. They will stuff their mouth with sand and spit it out elsewhere, slowly creating a tunnel. Utilizing the protection of these burrows, these fish will hover feeding on plankton or other small organisms, ready to dart back in at the first sign of danger. They are territorial of the area around their burrows.

Jawfish are mouthbrooders meaning that their eggs hatch in their mouths, where the new-born fry are able to be protected from predators. Mouthbrooding, also known as oral incubation and buccal incubation, is the care given by some groups of animals to their offspring by holding them in the mouth of the parent for extended periods of time.

Jawfish are paternal mouthbrooders, where the male looks after the eggs. Typically, after courtship, the male fertilises the eggs and then collects them in his mouth, holding onto them until they hatch. During this time he cannot feed. All mouthbrooding fish will be underweight and requiring a period of time to feed and make good the depletion of their energy reserves.
The eggs are protected until they hatch and the fry become free swimming. By caring for their offspring in this way, jawfish are able to produce smaller numbers of offspring with a higher chance of survival than species that offer no broodcare.